This invention relates to buildings, building components, building subassemblies, and building assemblies, and to methods of constructing buildings. The invention has particular application to building roof structures that incorporate rafters, purlins, braces that connect rafters to purlins (e.g. to enhance structural integrity), and suspension fabrics. The suspension fabric may be part of a fall protection system, part of an insulation support system, and/or part of a vapor barrier system. The invention also relates to associated articles, systems, and methods.
From time to time, injuries occur during the construction of buildings, including to workers involved in such construction. Workers who are involved, in particular, in the construction of roof structures for buildings are at risk of injury that may result from falling from an elevated height. Standard and required systems and practices have been developed to protect such workers, for example to catch and support them if/when they fall. These systems and practices are referred to as fall protection systems.
One known fall protection system is a passive system wherein a fabric, such as a solid sheet, a woven sheet, or a net-like material, is suspended at or below the work area, optionally supported by a grid of crossing support bands, far enough above any underlying supporting surface to catch and support a worker who falls, thereby to act as a passive fall-protection system.
The Occupational Safety and Health Administration (OSHA) in the U.S. has defined a drop test procedure whereby such a passive fall protection system can be tested. According to the test procedure, a 400 pound weight is dropped onto the fall protection system under stated conditions to determine whether a given system meets the required safety standards. For purposes of complying with government regulations, any system used as a fall protection system need only meet the OSHA-mandated standards related to dropping such 400 pound weight. Of course, the real humanitarian objective is to prevent worker injuries if/when a worker falls from an elevated work location. Thus, any fall protection system which is effective to catch and safely hold a falling worker has operational value, even if such system does not meet OSHA standards.
According to one practice currently in use in the metal building industry, and intended to meet government fall protection standards, a purported fall protection system uses crossing longitudinal and lateral metal bands extending under the eave, under the ridge, and under the intermediate purlins of the roof structure of the building, and a fabric is installed above the bands and under the purlins, extending across the entirety of a respective bay of the building being constructed, thereby providing a suspended fabric intended to catch and support a falling worker in that bay. Insulation is ultimately installed on the top surface of the fabric whereby the fabric ultimately functions both as the vapor barrier portion of the building ceiling insulation system in the finished building and as a catch-and-support fabric in the fall protection system.
In some cases, the design of a building roof structure calls for flange braces to be installed between the rafters and purlins of the building support structure. In some cases, a flange brace has a lower end which attaches to the bottom flange of a rafter, and an upper end which attaches to a neighboring purlin which is supported by the rafter. Such flange braces can enhance the structural integrity of the corresponding roof structure of the building.
However, such flange braces can also pose a challenge to the installation of a large suspension fabric which extends across the bay of a building roof structure. As such a fabric is unfolded in order to extend the fabric along the length of the bay underneath a set of successive purlins, the flange braces may present obstacles to such unfolding and installation of the extended fabric. One known approach to this situation is to disconnect the upper ends of the braces from the respective purlins so that the suspension fabric can be extended, and, after the fabric is in place, attaching the upper ends of the braces to bottom surfaces of the respective purlins. This approach avoids having to create a large hole or opening in the suspension fabric that would be needed to re-attach the upper end of each brace to a more central part of the respective purlin; however, attachment of the brace to the bottom surface of the purlin can be contrary to the building specification, and is otherwise undesirable from a structural integrity standpoint.
In another known approach, the upper ends of the braces are again disconnected from the respective purlins, but, after the extended suspension fabric is in place in the bay beneath the purlins and above the braces, a large opening is cut in the suspension fabric at a location corresponding to each brace so that the upper end of the brace can be re-attached to the respective purlin through such opening. Pieces of patch tape are then applied to the lower surface of the suspension fabric to repair the openings. In some cases, a sealant is also applied at the repair points, e.g. to restore the ability of the suspension fabric (as repaired) to act as a vapor barrier. However, the pieces of patch tape applied to the suspension fabric are typically visible to occupants of the building, e.g. after construction of the roof structure and building is complete, and can be highly unattractive. Furthermore, the patch tape can work loose and delaminate over time with normal expansion and construction of the building components.
Accordingly, there is a need for a novel approach to the challenge of constructing building roof structures which incorporate both extended suspension fabrics (e.g. as part of a fall protection system, or for insulation support, or for use as a vapor barrier) and flange braces which connect rafters to purlins in the roof structure.
These and other needs are alleviated, or at least attenuated, or partially or completely satisfied, by novel products, systems, and/or methods of the invention.